1. Field of the Invention
The present invention is generally related to optical devices and methods such as those used for surgery. In particular the present invention relates to techniques for enhancing the throughput and manipulation of optical information through a limited cross-section endoscopic relay. In one aspect, the invention provides an endoscope having an optical relay, objective, or ocular using at least one intermediate image formed within an optical component such as a glass element or lens. In another aspect, the invention provides an ocular system that permits independent adjustment of the diopters, magnification, X-Y positioning and rotational orientation of an image, while introducing minimal aberrations.
Minimally invasive medical techniques are aimed at reducing the amount of extraneous tissue which is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. The average length of a hospital stay for a standard surgery is significantly longer than the average length for the equivalent surgery performed in a minimally invasive surgical manner. Patient recovery times, patient discomfort, surgical side effects, and time away from work are also reduced with minimally invasive surgery.
The most common form of minimally invasive surgery may be endoscopy. Probably the most common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient""s abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately xc2xd inch) incisions to provide entry ports for laparoscopic surgical instruments.
The laparoscopic surgical instruments generally include a laparoscope for viewing the surgical field, and working tools defining end effectors. To perform surgical procedures, the surgeon passes these working tools or instruments through cannula sleeves to a desired internal surgical site and manipulates the tools from outside the abdomen. The surgeon often monitors the procedure by means of a television monitor which displays an image of the surgical site via the laparoscopic camera. Similar endoscopic techniques are employed in, e.g., arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like.
Minimally invasive telesurgical systems are now being developed to increase a surgeon""s dexterity, so that the surgeon performs the surgical procedures on the patient by manipulating master control devices to control the motion of servomechanically operated instruments. In such a telesurgery system, the surgeon is again provided with an image of the surgical site via an endoscope. In both telesurgical and manual endoscopic procedures, the endoscope may optionally provide the surgeon with a stereoscopic image to increase the surgeon""s ability to sense three-dimensional information regarding the tissue and procedure.
Endoscopes typically include three optical sub-systems: an objective lens system, an ocular lens system, and a relay lens system. The objective lens system is located at the distal portion of the endoscope to capture the desired image. The ocular lens system or eyepiece is located at the proximal portion of the endoscope and generally remains outside the patient body to transmit the desired image to the eye, camera, or the like. The relay lens system is generally disposed between the objective and ocular to transfer the image proximally out of the patient along a relatively small diameter endoscope shaft.
The objective lens system is typically separated from the relay system by an objective-relay air gap, while the relay system is separated from the ocular lens system by a relay-ocular air gap. The relay will typically be separated into a series of relay lens units, with the relay units again being separated by gaps. The objective lens system generally forms a first intermediate image in the objective-relay gap. The relay lens system then transfers this intermediate image from the distal portion of the scope toward the proximal portion by generating as many intermediate relay images as appropriate to travel the length of the shaft. A last intermediate image is produced by the relay system in the relay-ocular gap. The ocular collimates or nearly collimates this final intermediate image for detection by a surgeon""s eye via viewing lenses such as an eyepiece, or for transmission to the imaging optics of a camera, the camera optics typically forming a final image on a charge couple device (CCD) of the camera.
The ocular lens system of known monoscopic endoscopes typically has a plurality of lenses that can manipulate the captured image. The optical properties of the captured image can be modified to ensure proper viewing of the desired object within the body. While such adjustments may be adequate for monoscopic endoscopes, when imaging a target site with a stereo imaging optics, it is of particular importance to have very accurate adjustments between the stereo channels to provide accurate three dimensional information that can be matched between the two channels. If accurate matching is not accomplished, the stereo viewer will provide an inaccurate image and may cause eye strain for the user.
While these known monoscopic endoscopic structures and methods have been quite successful, and are now widely used for imaging of internal tissues and surgical sites via minimally invasive apertures, further improvements would be desirable. In general, it would be desirable to provide improved optical systems and methods. It would be particularly desirable if these improved optical techniques enhanced the amount of optical information which could be transmitted along an optical path having a given, relatively limited cross-section (and/or diminished the cross-section to transmit a given image). It would further be desirable to provide improved monoscopic and stereoscopic endoscopes with enhanced image quality and/or decreased cross-sectional dimensions for use in manual and robotic minimally invasive surgical procedures. Additionally, it would further be desirable to provide an ocular system which allows independent adjustment of the optical properties of the image, while limiting the amount of aberrations introduced. Moreover, it would further be desirable to provide endoscopes which have the sensitivity in its adjustments to allow matching (e.g., position, orientation, size, and simultaneous focus) of the left and right channels of a stereo endoscope.
2. The Background Art
The following U.S. Patents may be related to the present invention, and the full disclosures of each is hereby incorporated herein by reference: U.S. Pat. Nos. 5,568,312; 5,743,846; 5,743,847, 5,776,049; 5,861,987; and 5,956,179.
Robotic surgical systems which might make use of the improved imaging capabilities of the present invention are described in the following U.S. Patent Application Numbers, each of which is incorporated herein by reference: Ser. No. 09/378,173; filed Aug. 20, 1999; Ser. No. 09/433,120, filed Nov. 3, 1999; and Ser. No. 09/418,726, filed Oct. 15, 1999.
The present invention generally provides improved optical devices and methods for transmitting optical images along elongate optical paths with relatively limited cross-sectional dimensions, particularly for use in surgical endoscopes, boroscopes, periscopes, monoscopes, stereoscopes, and the like.
In one embodiment, the invention provides an endoscope having an objective, relay, and ocular lens system which have at least one intermediate image formed within an optical component, rather than being formed in a gap between optical components. Optical components will herein be used to mean a single lens, a compound lens, a rod lens, a glass element, or other optical elements which have a refractive index of greater than one. The optical component may or may not have surface contours. For example, if the intermediate image is formed in glass, the glass can act to prevent external elements, such as dust, from introducing aberrations into the image.
In an exemplary embodiment, the image-containing optical component will often be a lens within an integrally designed objective-relay (and/or relay-ocular) system. In contrast to standard endoscope systems, which rely on modular, independent designs for their objective lens systems, relay lens systems, and ocular lens systems, the optical train of the present invention need not form a highly corrected intermediate image at an image plane disposed between the objective and relay, and/or between the relay and ocular.
In a preferred embodiment, an intermediate image is formed within the glass of the most proximal objective lens, which extends proximally of the first intermediate image to a proximal surface adjacent the relay. Additionally, this intermediate image will often be allowed to distort or extend significantly along the optical axis (i.e., have a large field curvature) so as to define a curved image location within the glass. A final intermediate image may similarly be disposed within a distal lens of the ocular system. Other intermediate images may be formed in an optical element or gap within the relay lens system.
Surprisingly, by making use of a first and/or last intermediate image disposed within a lens of an integrally designed optical train, the endoscopes of the present invention will generally provide a significantly larger Numerical Aperture than known endoscopes having similar cross-sectional dimensions and length. Consequently, the optical train will produce a highly aberration corrected image with a better image resolution. Forming these intermediate images within glass also decreases the sensitivity of the image quality to dust and/or scratches, which further enhances the viewer""s ability to detect small details in the image.
In contrast to known endoscopes, which balance or correct the image at the objective lens system and ocular lens system independently, the endoscopes of the present invention will typically deliver a distorted or unbalanced image from the objective lens system through the relay lens system to the ocular lens system. After the distorted image has been delivered to the ocular lens system, the aberrations in the distorted image are balanced and compensated by the ocular lens system to produce the final image. By delivering an expanding, unbalanced, and distorted image to the ocular lens system, the endoscopes of the present invention are able to achieve a larger throughput relative to conventional endoscopes having the same cross section and length of endoscope, while at the same time reducing the amount of aberrations introduced into the image throughout the optical train. Consequently, a brighter, clearer final image can be created.
In one aspect, the invention provides an optical train for viewing an object. The optical train comprises an objective lens system for acquiring an image of the object and an ocular lens system for forming a final image of the object. A relay lens system is disposed along an optical path between the objective lens system and the ocular lens system. At least one of the objective lens system, relay lens system, and ocular lens system includes an optical element. An intermediate image is formed within the optical element.
Causing an image to coincide with an optical element instead of air, increases the ability of the optical train to image a particular object and causes the optical train to behave as if it had a much larger Numerical Aperture. The invention also permits the image to be less affected by dust or scratches on lens surfaces that would normally harm the image""s quality and so affect the viewer""s ability to detect small details in the image.
Optionally, the image-containing optical element may be a part of the objective lens system. Although the relay lens system may be separated from the objective lens system by an objective-relay gap, no intermediate image will typically be formed within the objective-relay gap. Alternatively or additionally, the first image-containing optical element may be a part of the ocular lens system, and similarly, no intermediate image need be disposed within an ocular-relay gap. Preferably, first and last intermediate images will be formed within the image-containing optical elements of the objective and ocular lens systems, respectively. The relay system may comprise a plurality of axially separated relay units, with the number of relay units being selected to transmit the image along the desired axial length. Such relay units may be uniform and interchangeable, with each relay unit including an axially symmetric set of relay lenses and glass elements. Additionally, glass elements may be disposed adjacent relay lenses such that other intermediate images are formed in the glass element. Additionally or alternatively, relay gap may be disposed between adjacent relay units so that an associated relay intermediate image is formed therein.
In another embodiment, the invention provides an endoscope comprising a shaft having a distal portion adjacent a distal end and a proximal portion adjacent a proximal end. An ocular lens system is disposed along the proximal portion, and a relay lens system is disposed along the shaft between the proximal portion and the distal portion. An objective lens system is disposed along the distal portion, with the objective lens system comprising an optical element. The objective lens forms a first intermediate image within the optical element.
In yet another embodiment, the invention provides an endoscope for presenting an image of an object to an eye of an observer. The endoscope comprises a scope body having a proximal portion adjacent a proximal end, and a distal portion adjacent a distal end, with an optical path therebetween. An objective lens system is disposed adjacent the distal portion for accepting light from the object and transmitting the light proximally. The objective lens system has an optical element with a distal surface and a proximal surface, and defines a first intermediate image of the object between the surfaces of (and within) the optical element. An ocular lens system is disposed adjacent the proximal portion for viewing the image with the eye adjacent thereto. A relay lens system is disposed between the objective and ocular lens systems, the relay system comprises a plurality of axially separated relay units.
The relay units can be interchangeable and each relay unit can comprise glass elements and an axially symmetric set of relay lenses. In some configurations, a relay gap is disposed between each pair of adjacent relay units so that an associated relay intermediate image is formed in the relay gap. In other configurations, the intermediate image is formed in the glass element. The relay lens system typically has a proximal lens with a proximal surface and a distal lens with a distal surface, and defines at least one intermediate relay image of the object between the proximal and distal lenses of the relay system.
In another aspect, the present invention provides a method of manipulating an image captured by a stereoscopic endoscope. A diopters of the captured image is set. The magnification of an image is independently altered without significantly affecting the diopters. The X-Y positioning of the image is adjusted without introducing aberrations or affecting the diopters and magnification, and an orientation of the captured image is rotated such that the rotation of the image does not affect the diopters, magnification, and X-Y positioning of the captured image.
In still another aspect, the present invention provides a method of manipulating an image within a stereoscopic endoscope which has a first lens, second lens, a third lens, and a prism positioned in an optical path of the ocular system. The method includes moving the lenses of the ocular system along the optical path to adjust a diopters of the endoscope. The position of the first lens is maintained while the second and third lens are moved to adjust the magnification of the image. An orthogonal position of the second lens is adjusted to adjust the X-Y position of the image. The prism is rotated to adjust the rotational orientation of the image.
In a further aspect, the present invention provides a stereoscopic endoscope. The endoscope includes a first channel having a first optical path and a first objective lens system optically coupled to a first ocular lens system through a first relay system. A second channel having a second optical path and a second objective lens system optically coupled to a second ocular lens system through a second relay system is positioned adjacent to the first channel. The first ocular lens system and the second ocular lens system each comprise a first and second positive lens and a negative lens disposed in the optical paths. The negative lenses can be moved off the optical paths so as to stereo match the first channel with the second channel.
The X-Y positioning of the image can be adjusted so that there are reduced (less than 1%) aberrations introduced into the diopters and magnification. The orientation of the captured image can also be independently adjusted without affecting the diopters, magnification, or X-Y positioning of the image.
In yet another aspect, the present invention provides a method of manipulating an image. The method includes capturing an image with an objective lens system. An unbalanced image is relayed through a relay lens system to an ocular lens system. The relay (unbalanced) image is balanced within the ocular system to produce the final image.
In many configurations, the unbalanced image is distorted and expanding. Such a configuration therefore can provide the maximum throughput of optical information through the lens systems. This permits better image resolution and improved image brightness, relative to a conventional lens systems in which the objective and ocular systems are independently balanced.
In still another embodiment, the present invention provides a stereoscopic endoscope. The endoscope includes a shaft having an objective lens system positioned on a distal end of the shaft. A relay lens system is disposed in the shaft, proximal of the objective lens system. An ocular lens system is coupled to a proximal end of the shaft and includes a prism having a wedge at a proximal end for bending light rays to create a stereo line of convergence.
These and other aspects of the invention will be further evident from the attached drawings and description of the embodiments of the invention.